CTC PRUSA i3 Pro B Bowden Drive with Autoleveling

UPDATE 3/15/2018
Rossano95 shared his modified retainer. I removed the non-working and replaced it with his. Give Rossano95 a shout out if you use it! ;-)

UPDATE 3/14/2018
Rossano95 tested the 18mm mount version and it worked! The retainer didn't fit very well so he redesigned it. He may post as a remix or if he sends it to me I'll post it here.

UPDATE 3/11/2018
I added a untested hotend mount for a 18mm sensor. I don't plan on ever using it, so print it at your own risk.

UPDATE 1/6/2018
The blasted 2mm glass worked great...for a while. Unfortunately the last print stuck too good to the blasted glass and some glass came off when I pulled the part off. So I'm I went back to the hardware store and picked up another piece of glass. Adhesion is just fine with Ammonia cleaned class (Windex or any off brand window cleaner), but not as good as the blasted glass.

UPDATE 12/30
I decided to print the STL and it turned out great. I put in 4 brass inserts and then mounted the whole thing from the back in the lower position via the brass inserts instead of the lower mounting holes. I also bead blasted the glass which seems to help with adhesion. Please note that the duct is adjustable via the oval mounting holes. I had to mount it in the all the way up position to give it clearance between the nozzle and the bed.

My CTC hotend broke and I was without a 3D printer. Luckily, I am in the process of building a HEVO and therefore I had the mount, hotend, extruder, retainer and duct already on hand. By drilling two extra holes and removing a little plastic near the X endstop flag in the mount, I made it fit the CTC carriage perfectly. Again, since my printer was down, I didn't design this in CAD and just modified the piece I had by hand and then created the STL for thingiverse so no guarantees that it will fit. I left a bridge in there for support that you will have to break out and I put in two mounting options; one way the way I mounted it by drilling holes, and another for mounting it with M3 brass fittings to lower the mount closer to the bed. The HEVO mount has the proximity probe spot already, so I figured I should add that sensor as well.

If you are ready for a double mod, keep reading...

Items Needed:
- Soldering Iron
- several connectors
- connector wires (from breadboard)
- Arduino IDE
- an extra Arduino as ISP to update the bootloader on the CTC Aduino
- Marlin firmware

BOM:
- 1 x 5V NPN M12 inductive sensor
https://www.aliexpress.com/item/M12-4mm-detection-5VDC-NPN-NO-LJ12A3-4-Z-BX-5V-cylinder-inductive-proximity-sensor-switch/32553311139.html?spm=2114.13010608.0.0.iDrnoz

• 3D Printer Accessories V6 J-Head Hotend RepRap Extruder for 1.75mm Filament, Direct Feed or Bowden. w/ 0.4mm Nozzle, 12V fan, and 3ft PTFE Bowden Tube
  ALPTA
  http://a.co/9PxYSl4

• 8.5" x 8.5" galvanized 28ga metal plate to place between the hotbed and glass plate. This ensures that the sensor is triggered properly. Without it you will need to either not use glass or you are going to be very close to the nozzle level. Ferrous metals are the best at triggering proximity sensors, that's why I didn't use aluminium.

• 8.5" x 8.5" x 0.880" glass plate. I prefer to print on glass.

• Extruder of your choice (e.g. find one on thingiverse)

Process

1. Prepare and install your material for your heat bed. Cut the galvanized plate with some metal shears to size. IMPORTANT: make sure the metal does not short out any contacts on the heated bed. You need to cut around those areas!.
   

2. Get the glass plate from your a hardware store. They will cut it to size if you ask nicely. You need the corners angled to have room for the screw heads.

3. Prepare and install the J hotend and proximity sensor with the extruder mount, retainer and duct from the HEVO project.

4. Solder the 5V and Ground connections to the board. I chose to use add a connector for easy disconnect.

5. Make a backup of the original settings. These were mine:
   
   15:07:46.286 : echo:Hardcoded Default Settings Loaded
   15:07:46.286 : echo:Steps per unit:
   15:07:46.287 : echo: M92 X78.74 Y78.74 Z2560.00 E105.00
   15:07:46.287 : echo:Maximum feedrates (mm/s):
   15:07:46.287 : echo: M203 X400.00 Y400.00 Z2.00 E45.00
   15:07:46.287 : echo:Maximum Acceleration (mm/s2):
   15:07:46.287 : echo: M201 X1400 Y1400 Z100 E80000
   15:07:46.287 : echo:Acceleration: S=acceleration, T=retract acceleration
   15:07:46.287 : echo: M204 S1400.00 T5000.00
   15:07:46.287 : echo:Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum XY jerk (mm/s), Z=maximum Z jerk (mm/s), E=maximum E jerk (mm/s)
   15:07:46.287 : echo: M205 S0.00 T0.00 B20000 X13.50 Z0.30 E5.00
   15:07:46.287 : echo:Home offset (mm):
   15:07:46.287 : echo: M206 X0.00 Y0.00 Z0.00
   15:07:46.287 : echo:PID settings:
   15:07:46.287 : echo: M301 P19.86 I1.00 D98.93

6. Upgrade your bootloader. Here is how to do it:
   NOTE: I simply used the standard SD card cable and plugged in bread board wires into the one end. So I didn't need to find a ribbon cable that I could cut up! I also added a pictures of the connectors.

7. Time to download, configure and install Marlin. Use the GEEETECH example in the examples folder as a base. I attached my Configuration.h file here for reference with auto leveling enabled: https://www.thingiverse.com/download:4494314 . Using this config will consume 94% of the memory. So there is hardly anything left for additional features.

8. Last but not least make sure you adjust the z-axis in the LCD until you get the nozzle in the correct location (mine was -0.25). Then make sure you save your settings.

ANOTHER BENEFIT of UPGRADING YOUR FIRMWARE*
The CTC is over-extruding (at least mine was). In Cura I had set the correction in the start script, but with the new firmware I changed the E stepper from 105 to 95 in the configuration.h, so no more start code fix needed!